Re: [gtk-gnutella-devel] #error "float must use IEEE 754."

[jgoerzen <jgo...@op...>]

On 04/06/2014 03:53 AM, Raphael Manfredi wrote:
> Quoting Jake Goerzen <jgo...@op...> from ml.softs.gtk-gnutella.devel:
> :I'm trying to compile GTKG version 1.0.1 on solaris 10 for OpenCSW.org
> :but I get a compile error (see below).  During Configure I noticed this:
> :
> :Checking IEEE-754 float byte-ordering... not using IEEE-754 here.
> :
> :It appears that the machine byte-order is not getting identified.
> :Several years ago I got it compiled successfully (version 0.96.3) but I
> :forgot what I did to get it to work. Perhaps ieeefp.h needs to be
> :included somewhere?
>
> There may be a problem with the test that is done to detect IEEE-754.
>
> The way it's done is the following: I encoded an array of floating point
> values that, when compiled in the executable, build up an ASCII string.
> The Configure test then looks up the string in the .o file to determine
> that IEEE-754 is used, and whether it's little or big-endian.
>
> However, this assumes the "float" type encodes values on 4 bytes.
> Is this the case with your CPU architecture and compiler?  If the "float"
> C type is encoded on more than 4 bytes, then the check will indeed fail.
>
> If you can tell me how large your "float" and "double" types are on your
> machine, that would help.
>
> This simple C program will do the trick:
>
> ------------
> #include <stdio.h>
>
> main()
> {
>          printf("sizeof(float) = %u\n", sizeof(float));
> 		printf("sizeof(double) = %u\n", sizeof(double));
> 		return 0;
> }
> ------------
>
> If you can stuff that in a "bar.c" file, then type "make bar" and
> then "./bar", please send me the output...
>
> Thanks,
> Raphael
>
>
Hello Raphael,  This is the results that I get:

% make bar
cc    -o bar bar.c
"bar.c", line 4: warning: old-style declaration or incorrect type for: main
% ./bar
sizeof(float) = 4
sizeof(double) = 8

Thanks,
Jake